Daraqutni

Abu Ahwas narrates: On the day of the Battle of Nahrawan, we were on one side of the river with Sayyiduna Ali ibn Abi Talib (may Allah be pleased with him), when the Kharijites came and camped on the other side of the river. Sayyiduna Ali (may Allah be pleased with him) said: "Do not provoke them, unless they themselves commit any wrongdoing." Those people went to Abdullah ibn Khabbab and said: "Tell us a hadith that your father narrated to you, which he heard from the Prophet Muhammad (peace and blessings be upon him)." So Abdullah ibn Khabbab said: "My father narrated to me that he heard the Prophet Muhammad (peace and blessings be upon him) say: 'A time of tribulation will come in which the one who is sitting will be better than the one who is standing, and the one who is standing will be better than the one who is running.'" (The narrator says:) Those people (i.e., the Kharijites) took him (i.e., Abdullah ibn Khabbab) to the bank of the river and slaughtered him as a goat is slaughtered. When this news reached Sayyiduna Ali (may Allah be pleased with him), he said: "Allahu Akbar!" and said: "Call out to them loudly, say that they should send the killer of Abdullah ibn Khabbab to us." So those people replied three times: "We all killed him." Then Sayyiduna Ali (may Allah be pleased with him) said to his companions: "Now attack them." The narrator says: After that, Sayyiduna Ali (may Allah be pleased with him) and his companions killed those people. The narrator says: After that, (the one narrating) narrated the rest of the narration.